Scheme for managing nodes connected to a home network according to their physical locations

ABSTRACT

A scheme for managing nodes connected to a home network according to their physical location is disclosed. A communication device constituting each node is formed by at least one communication unit for carrying out communications through a connected network, having communication ports for connecting nodes through which data are to be exchanged by the nodes, and a configuration information memory unit for storing a configuration information regarding a configuration of the communication device, having a region for dynamically describing a location information regarding a physical location of the communication device. At a managing node, a configuration information of a connected network and a location information regarding a physical location of a prescribed node connected to the network are collected, and physical locations of other nodes/services that are connected to the prescribed node are managed by regarding the other nodes/services as existing at an identical physical location as the physical location of the prescribed node as specified by the location information.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a scheme for managing a networkutilizing information outlets in a home network environment.

[0003] 2. Description of the Background Art

[0004] In recent years, there is a rapid trend for digitalizingelectronic devices as exemplified by advances of the multi-mediatechnology, and this trend is already noticeable in the officeenvironment.

[0005] In terms of hardware, this trend has been materialized in formsof introduction of PCs, digitalization of OA devices and formation ofnetworks among them. Also, in terms of software, this trend has beenexpanding to cover the basic functions of hosts (which are progressivelylight-sized and transferred to PCs), the application software such asthe word-processing software, the spreadsheet software, etc., and theInternet application such as the WWW.

[0006] The similar trend can also be seen in the home environment forhome use devices and related fields. Namely, even in the homeenvironment, this trend for digitalization has been steadily progressedin forms of digitalization of AV devices (DVD, digital VTR, digitalvideo camera, etc.), digitalization of broadcasting, and Internet accesssuch as OCN.

[0007] This trend of technological innovations that has started from theoffice environment is expected to progress toward the formation ofnetworks in future. Namely, it is expected that the technologies ofvarious fields such as information processing, communication andbroadcasting will be unified by the digitalization, and inter-mixed witheach other by the formation of networks.

[0008] There are many candidates for the network technologies thatprovide the bases for this trend. For example, the Ethernet hasoverwhelming records of the actual use in the office environment and isprobably the most promising candidate even for the home PC network.Also, the ATM is another serious contender because of the generalconsensus among the infra-structure constructors (telephone companies,CATV companies, etc.) to keep constructing the infra-structures based onthis technology in view of the advantageous characteristics of the ATMsuch as its fast, real-time, and wide bandwidth properties.

[0009] In addition to these candidates, the network technology (bustechnology) called IEEE 1394 has been attracting much attentionsrecently. This IEEE 1394 has several remarkable characteristics such asits fast, real-time (QOS guaranteed), and plug-and-play properties, sothat there is a high expectation especially among the AV industries onthe IEEE 1394 as the most promising candidate for a future scheme forinter-connecting digital AV devices. This vogue has also instigated muchinterests to the IEEE 1394 from the computer industries as well.

[0010] In the initial phase, it is expected that the inter-connection ofthe home use digital devices by these various network technologies willbe realized in conjunction with the spread of the home use digitaldevices, depending on preferences and demands of the users, and in thisway prototype digital networks will be gradually built up inside eachhome. When these digital networks become more widespread, it isconceivable that a home will come to be equipped with “informationoutlets” in the similar manner as the electric outlets commonly found inour homes today.

[0011] Namely, similarly as the currently used electric outlets,dedicated outlets for the purpose of making connections to the homenetwork will be provided at each room or any other convenient locationwithin a home. These information outlets are inter-connected eitherdirectly or via bridges behind the wall, for example, so as to providean infrastructure capable of easily realizing things like “AV datatransfer from this room to that room”.

[0012] In the IEEE 1394 mentioned above, in order to realize suchinformation outlets, the so called “long haul 1394” which is capable ofensuring a cable length of over 50 meters is currently under thediscussion, and its use in realization of the domestic informationoutlets will be quite promising.

[0013] Now, in the current network management, the network configurationinformation (such as an information regarding a node that exists in thenetwork or an information regarding a service that is provided in thenetwork, for example) is discriminated according to MAC address, IPaddress, host name (domain name) or the like that is assigned to eachnode, and displayed on a screen of the network management terminal andthe like. In general, the network manager is an expert in the networkart so that he basically encounters no difficulty in a situation likethat.

[0014] However, in the home network, actual nodes will be the home usedevices such as TV, VTR and camera, and it is quite difficult to expecta general home use device user to be capable of handling such a nodemanagement and a network management that requires the naming of thesenodes by domain names or even worse discriminating these nodes accordingto MAC addresses.

[0015] What seems the most simple and convenient way of doing the samein the home network is to relate locations and devices, as in “the TV onthe second floor”, “the DVD in the reception room”, and so on. This wayis intuitively easy to comprehend speaking from our everyday lifeexperiences.

[0016] However, it has been difficult to realize this because of thefollowing problem. Namely, in the link layer network technologies mostnotably represented by IEEE 1394 and Ethernet, there is a concept ofnode “connection” but there is not concept of node “location”. Namely,it is possible to recognize things like “this node is connected to thenetwork” or “the node A is connected next to the node B”, but there hasbeen simply no way of recognizing a physical location at which the nodeis actually located in such a manner as “this node is located in thereception room”.

[0017] For this reason, it has been impossible to present the nodes inrelation to their physical locations to the user, or identify nodes inrelation to their physical location, for example, and this fact has beenthe major obstacle in constructing a home network in which thesimplification of a network management is indispensable.

SUMMARY OF THE INVENTION

[0018] It is therefore an object of the present invention to provide ascheme for managing nodes connected to a home network according to theirphysical location.

[0019] Specifically, the present invention provides a communicationdevice, a network information management method, and a locationinformation notification method that can be used in realizing such anetwork node management scheme.

[0020] According to one aspect of the present invention there isprovided a communication device, comprising: at least one communicationunit for carrying out communications through a connected network, havingcommunication ports for connecting nodes through which data are to beexchanged by the nodes; and a configuration information memory unit forstoring a configuration information regarding a configuration of thecommunication device, having a region for dynamically describing alocation information regarding a physical location of the communicationdevice.

[0021] In this aspect of the present invention, it becomes possible toenable the other communication device to recognize a physical location(such as living room, children's room, etc.) at which this communicationdevice is located, through the configuration information memory unitsuch as a configuration memory. In particular, it is quite useful in thecase of identifying a physical location of a communication device whichcan be regarded as not moving in general, such as an information outletembedded in the wall.

[0022] According to another aspect of the present invention there isprovided a communication device, comprising: a plurality ofcommunication units for carrying out communications through a connectednetwork, each communication unit having communication ports forconnecting nodes through which data are to be exchanged by the nodes;and a configuration information memory unit for storing a configurationinformation regarding a configuration of the communication device,having a region for dynamically describing a location informationregarding a physical location of each communication unit.

[0023] In this aspect of the present invention, it becomes possible toenable the other communication device to recognize a physical locationat which each communication unit is located, through the configurationinformation memory unit such as a configuration memory.

[0024] According to another aspect of the present invention there isprovided a communication device, comprising: at least one communicationunit for carrying out communications through a connected network, havingcommunication ports for connecting nodes through which data are to beexchanged by the nodes; and a configuration information memory unit forstoring a configuration information regarding a configuration of thecommunication device, having a region for describing an informationregarding whether the communication device is movable or immovable.

[0025] In this aspect of the present invention, it becomes possible toenable the other communication device to recognize whether thiscommunication is movable or immovable, through the configurationinformation memory unit such as a configuration memory. In particular,in the case of identifying a physical location of a communication devicewhich can be regarded as not moving in general, such as an informationoutlet embedded in the wall, a node connected to that information outletlocated at the identified physical location can be regarded as beinglocated at the same physical location (the same room, for example) asthat information outlet in general. This can also be asserted from thefact that in general a length of a network cable (for example, a lengthof an electricity cable of the IEEE 1394) is short (4.5 m).

[0026] According to another aspect of the present invention there isprovided a communication device, comprising: at least one communicationunit for carrying out communications through a connected network, havingcommunication ports for connecting nodes through which data are to beexchanged by the nodes; and a configuration information memory unit forstoring a configuration information regarding a configuration of thecommunication device, having a region for describing an informationindicating a communication port which is a leaf of a network structureamong the communication ports.

[0027] In this aspect of the present invention, it becomes possible toenable the other communication device to recognize which communicationport of this communication device corresponds to a leaf, through theconfiguration information memory unit such as a configuration memory. Inparticular, in the case of identifying a physical location of acommunication device which can be regarded as not moving in general,such as an information outlet embedded in the wall, a node connected toa leaf of that information outlet located at the identified physicallocation can be regarded as being located at the same physical location(the same room, for example) as that information outlet.

[0028] According to another aspect of the present invention there isprovided a communication device, comprising: a configuration informationcollection unit for collecting a configuration information of aconnected network; a location information collection unit for collectingat least a location information regarding a physical location of aprescribed node connected to the network; and a management unit formanaging physical locations of other nodes/services that are connectedto the prescribed node, by regarding the other nodes/services asexisting at an identical physical location as the physical location ofthe prescribed node as specified by the location information.

[0029] In addition, this communication device may further comprises adisplay unit for displaying to a user the physical locations of theother nodes/services as identical to the physical location of theprescribed node as specified by the location information.

[0030] Moreover, in this communication, the location informationcollection unit may also collect an information regarding a regioncorresponding to a leaf of the prescribed node, and the management unitmay manage physical location of selected other nodes/services that areconnected to the region corresponding to the leaf of the prescribed nodealone, by regarding the selected other nodes/services as existing at theidentical physical location as the physical location of the prescribednode as specified by the location information.

[0031] In this aspect of the present invention, it becomes possible toconjecture that the other nodes/services that are connected to theprescribed node on the network or the other nodes/services that areconnected to a region corresponding to a leaf portion of the prescribednode on the network are existing in a vicinity (the same room, forexample) of the identified physical location of the prescribed node, sothat it becomes possible to display these other nodes/services asexisting in a vicinity (the same room, for example) of the identifiedphysical location of the prescribed node, at the display unit withrespect to the user. Also, in general, the user of devices at home has atendency for identifying a device by the correspondence between thelocation and the device, as in “the VTR in the reception room” or “therefrigerator in the kitchen”, and according to the present invention, itbecomes possible to provide a network management scheme which is incompliance with this tendency.

[0032] According to another aspect of the present invention there isprovided a communication device, comprising: at least one communicationunit for carrying out communications through a connected network, havingcommunication ports for connecting nodes through which data are to beexchanged by the nodes; a memory for storing a location informationregarding a physical location of the communication device; and a replyunit for returning a reply packet containing the location information asstored in the memory, to a node that is a source of a query packetthrough the communication unit, upon receiving the query packet forinquiring a physical location of the communication device through thecommunication unit.

[0033] In this aspect of the present invention, it becomes possible toreply an information on a physical location of this communicationdevice, such as “reception room”, “children's room on the second floor”,or “the third floor of the XXX department store at the Shinjukustation”, with respect to an entity (a node, for example) which hasinquired such an information. Also, by implementing this procedure in aform which is unrelated to the lower layer technologies, it is alsopossible to realize a location query mechanism that is applicableregardless of the network type.

[0034] According to another aspect of the present invention there isprovided a communication device, comprising: at least one communicationunit to which a single link layer ID is given, for carrying outcommunications through a connected network, having a plurality ofcommunication ports for connecting nodes through which data are to beexchanged by the nodes; and a network layer processing unit for carryingout a network layer processing related to the communications, byassigning different network layer addresses to the communication ports.

[0035] In this aspect of the present invention, even in the case wherevalues of the link layer ID that can be given to the communicationdevices are to be limited, it is possible to effectively disregard sucha limitation as far as network layer addresses are concerned (forexample, IPv6 has an address space of 128 bits), so that it becomespossible to provide a network layer processing unit at eachcommunication port and thereby realize an intelligent communication porthaving various functions such as network layer implementation of thelocation query protocol, implementation of power consumption queryprotocol, filtering of passing data, etc.

[0036] Also, in this communication device, when a packet destined to thelink layer ID given to the communication unit is received from onecommunication port through the connected network, the network layerprocessing unit broadcasts at least a part of the packet with respect toother communication ports different from said one communication port ifthe packet is destined to a network layer address different from onenetwork layer address assigned to said one communication port.

[0037] In this case, it becomes possible to deliver a network layerpacket that is allocated to some specific communication port to acommunication port which properly has that network layer address. Thisis because it cannot specify the destination communication port of thenetwork layer packet according to the link layer ID alone in this case,but it becomes possible to deliver the network layer packet properly tothat network layer processing unit by using the above describedbroadcast function. Also, by using the broadcast information, it alsobecomes possible to reduce works, hardware amount and memory amount thatare required in preparing the routing table of network layer addressesinternally and carrying out the routing.

[0038] According to another aspect of the present invention there isprovided a network information management method in a communicationdevice having at least one communication unit for carrying outcommunications through a connected network, the method comprising thesteps of: collecting a configuration information of the connectednetwork; collecting at least a location information regarding a physicallocation of a prescribed node connected to the network; and managingphysical locations of other nodes/services that are connected to theprescribed node, by regarding the other nodes/services as existing at anidentical physical location as the physical location of the prescribednode as specified by the location information.

[0039] According to another aspect of the present invention there isprovided a location information notification method in a communicationdevice having at least one communication unit for carrying outcommunications through a connected network and a memory for storing alocation information regarding a physical location of the communicationdevice, the method comprising the steps of: receiving a query packet forinquiring a physical location of the communication device through thecommunication unit; and returning a reply packet containing the locationinformation as stored in the memory, to a node that is a source of thequery packet through the communication unit.

[0040] Other features and advantages of the present invention willbecome apparent from the following description taken in conjunction withthe accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0041]FIG. 1 is a schematic diagram showing an exemplary state ofinformation outlets provided in a home according to the embodiments ofthe present invention.

[0042]FIG. 2 is a diagram showing an exemplary state ofinter-connections among the information outlets shown in FIG. 1.

[0043]FIG. 3 is a diagram showing an exemplary state of devicesconnected to the information outlets shown in FIG. 1.

[0044]FIG. 4 is a diagram showing an exemplary format of an informationto be stored in a configuration memory of each information outletaccording to the first embodiment of the present invention.

[0045]FIG. 5 is a diagram showing an exemplary display screen fordisplaying an information on a physical location of each deviceaccording to the first embodiment of the present invention.

[0046]FIG. 6 is a sequence chart for a procedure to inquire a locationinformation to each node according to the second embodiment of thepresent invention.

[0047]FIG. 7 is a diagram showing an exemplary packet format for alocation query packet used in the procedure of FIG. 6.

[0048]FIG. 8 is a diagram showing an exemplary packet format for alocation reply packet used in the procedure of FIG. 6.

[0049]FIG. 9 is a flow chart for an operation of a network managementprogram which is an IP application according to the second embodiment ofthe present invention.

[0050]FIG. 10 is a diagram showing an information outlet group nodeaccording to the third embodiment of the present invention.

[0051]FIG. 11 is a diagram showing a topology of the information outletgroup node according to the third embodiment of the present invention.

[0052]FIG. 12 is a diagram showing an exemplary format of an informationto be stored in a configuration memory of the information outlet groupnode according to the third embodiment of the present invention.

[0053]FIG. 13 is a diagram showing an information outlet group nodeaccording to the fourth embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0054] Referring now to FIG. 1 to FIG. 13, various embodiments of anetwork node management scheme according to the present invention willbe described in detail.

[0055] <First Embodiment>

[0056]FIG. 1 shows an exemplary state of information outlets provided ina home. In this example, the IEEE 1394 information outlets 11 to 15 areprovided at a living room, a children's room, an entrance, a receptionroom, and a kitchen of the home respectively. These information outlets11 to 15 are inter-connected as shown in FIG. 2, for example. Usually,the information outlets 11 to 15 are inter-connected behind the walls ofthe home.

[0057] In this first embodiment, each one of these information outlets11 to 15 constitutes a single IEEE 1394 node. Namely, each one of theseinformation outlets 11 to 15 has one IEEE 1394 node ID by itself.

[0058] A device (node) connected to the information outlet in thisembodiment is capable of carrying out data communications with the othernodes through IEEE 1394 bus, and assumed to have a function forcontrolling other devices (nodes) by the datalink level or upper layerprotocol and/or a function for receiving controls from other devices(nodes).

[0059]FIG. 3 shows an exemplary state where various devices areconnected to the information outlets in the home of this example.Namely, a TV 31 and a VTR 32 are connected to the information outlet 11of the living room, a TV 33, a DVD 34 and a PC 35 are connected to theinformation outlet 12 of the children's room, a monitoring camera 36 isconnected to the information outlet 13 of the entrance, and a TV 37 anda karaoke device 38 are connected to the information outlet 14 of thereception room, while no device is connected to the information outlet15 of the kitchen.

[0060] This implies that the TV 31 and VTR 32 at the living room, the TV33, DVD 34 and PC 35 at the children's room, the monitoring camera 36 atthe entrance, and the TV 37 and karaoke device 38 at the reception roomare connected to respective information outlets, that is, to the IEEE1394 bus that constitutes the home network, while there is no IEEE 1394device at the kitchen except for the information outlet 15 itself.

[0061] In the exemplary device connection shown in FIG. 3, there arealtogether thirteen IEEE 1394 nodes including five information outletsthemselves and eight devices on the IEEE 1394 bus of this home.

[0062] Note that when the information outlets are connected togetherthrough bridges, there are cases where it is necessary to account forthe number of bridge devices or the number of ports of the bridgedevices in the number of IEEE 1394 nodes.

[0063] Now, in the network of the configuration as described above,consider a case of remote controlling the VTR 32 in the living room fromthe PC 35 in the children's room. Here, the remote control is anoperation to make a video recording reservation on the VTR 32 in theliving room or to playback a video on the VTR 32 in the living room anddisplay it on the TV 33 in the children's room, for example.

[0064] In this case, it is very convenient if a user in the children'sroom can specify the control target VTR very literally as “VTR in theliving room”, for example. In general, introduction of the networkmanagement/domain name concept of the computer network such as “let'sname this VTR vtr.living.takahashi.tokyo.jp” directly to the user shouldpreferably be avoided, although a partial use of such a concept might bepossible in some cases.

[0065] For this reason, the network management mechanism of this firstembodiment recognizes a device connected to some information outlet asbeing located at the same physical location as that information outlet.For example, “an IEEE 1394 device connected to the information outlet atthe living room” is regarded as “existing in the living room”. Then, thedevice connected to the information outlet provided at the living roomis presented to the user as “existing in the living room”.

[0066] To this end, there is a need for a node connected to the networkto recognize things like “which information outlet is provided at whichroom”. For this reason, in this first embodiment, a register, i.e., aconfiguration memory within each 1394 node stores at least informationregarding a physical location of the node. A memory position to writethis information, i.e., a register address is uniquely set up in advancein the 1394 address space (the identical address is set up for all 1394nodes). Here, it is preferable to have this address value predeterminedby the standardization organization such as IEEE or 1394 TA (TradeAssociation), for example, so that compatible devices can be produced bymanufactures who are adopting such a predetermined value.

[0067]FIG. 4 shows an example of information to be stored in theconfiguration memory. In this example, the configuration memory of each1394 node stores a node information (such as a vender ID, a nodecapability, an information capable of specifying a type or specificationof a device, etc.) which is the basic information regarding that node,as well as an information regarding a physical location of the nodewhich is entered as a location information at a dedicated unit dependentdirectory for storing the location information that is provided at apredetermined position (offset) of the configuration memory.

[0068] As for the content of the information regarding the physicallocation that is to be stored in this configuration memory, variouschoices are available.

[0069] One choice is to describe the concrete information regarding alocation such as “first floor”, “second floor”, “reception room”,“living room”, “bed room”, “right” and “left” by text using the officiallanguage of the intended country of use,

[0070] Another choice is to describe codes encoding the concreteinformation regarding a location such as “first floor”, “second floor”,“reception room”, “living room”, “bed room”, “right” and “left”. Notethat, as mentioned above, this information should preferably be coded asthe international standard by the public organization such as IEEE.

[0071] Still another choice is to describe identification numbersuniquely assigned to the information outlets at least within the home,and use a computer to carry out a processing for establishingcorrespondences between the identification numbers and the concreteinformation regarding a location such as “first floor”, “second floor”,“reception room”, “living room”, “bed room”, “right” and “left”.

[0072] In addition to such an information regarding a location, it isalso possible to describe an information regarding whether that node ismovable or immovable as a part of the location information. The abovedescribed provision to regard a node connected to the information outletof the living room as existing in the living node already presupposesthat the information outlet is fixedly provided at the living room, sothat it is particularly useful for the location information to specifywhether that node is movable or immovable, especially in the case of theinformation outlet.

[0073] Also, the IEEE 1394 specifies to attach port numbers to ports ofthe nodes. For example, in FIG. 2, it is assumed that the informationoutlet 11 has two ports corresponding to 111 and 112, the informationoutlet 12 has three ports corresponding to 121, 122 and 123, theinformation outlet 13 has two ports corresponding to 131 and 132, theinformation outlet 14 has three ports corresponding to 141, 142 and 143,and the information outlet 15 has three ports corresponding to 151, 152and 153.

[0074] In the 1394 nodes that constitute the information outlets, ports(111, 121, 131, 141 and 151 of FIG. 2) to be exposed outward as theinformation outlets are always leaves of a tree from a viewpoint of theIEEE 1394 topology. This implies that if a port that is a leaf in theIEEE 1394 tree constituting the home network is detected, and if thisnode has a fixed physical location (which can be recognized clearly fromthe above described information indicating that it is immovable), thenit can be said that a node connected to that port is (or highly likelyto be) existing at the same location as the node that has that port. Forexample, a node that is connected to a leaf port of a node having theinformation corresponding to “living room” on its configuration memory(which also has the information indicating that it is immovable) can beregarded as existing in the “living room”.

[0075] Consequently, it is preferable to describe an information as towhich port is a leaf, that is, the port number of a port that is a leaf,as the node attribute information on the configuration memory of eachnode. In this first embodiment, this information is described on theconfiguration memory as shown in FIG. 4.

[0076] Note here that, instead of describing the information regarding aleaf port, it is also possible to adopt such a scheme that a node thatis connected to a node having the information corresponding to “livingroom” on its configuration memory, and which can be recognized as a nodeother than the information outlet from the node information on theconfiguration memory, will be regarded as existing in the “living room”,for example.

[0077] Assuming that all of the information regarding a physicallocation, the information regarding movable/immovable and theinformation regarding a leaf port are to be described, in theconfiguration memory of the information outlet 11, the informationcorresponding to the living room as the location information, theinformation indicating that it is immovable, and the port number(corresponding to 111 of FIG. 2) that is a leaf, will be described.

[0078] In general, it appears customary to carry out the registration ofsuch information at a time of construction of the network, but a timingfor the registration of such information is not particularly limited inthis first embodiment. It also goes without saying that it is preferableto make it possible to carry out the rewriting of such information(rewriting the location information that is initially registered as“room-1” into “children's room”, for example).

[0079] Now, the above described example of remote controlling the VTR 32in the living room from the PC 35 in the children's room will bereconsidered.

[0080] In the IEEE 1394, it is possible to recognize the IEEE 1394network topology through the exchange of self ID packets which is theinitialization phase of bus/network. In conjunction with this, the PC 35can recognize that the information outlet 11 exists in the living roomso that the TV31 and VTR 32 that are connected thereto also exist in theliving room, by reading the information regarding a physical location onthe configuration memory of each node through the IEEE 1394 network.Similarly, the PC 35 can also recognize that the information outlet 12,TV 33, VTR34 and PC 35 exist in the children's room, the informationoutlet 13 and monitoring camera 36 exist in the entrance, theinformation outlet 14, TV 37 and karaoke device 38 exist in thereception room, and the information outlet 15 exists in the kitchen.

[0081] Note that it is also possible to recognize the device attributeof each node, such as an information that this node is TV or this nodeis DVD, for example, from the node information described in theconfiguration memory.

[0082] The PC 35 can display on its screen a result of the abovedescribed recognition, that is, an information on type and physicallocation of each device that is obtained by reading and collecting theinformation regarding a physical location and the information regardinga device attribute on the configuration memory of each node. Anexemplary display that can be used here is shown in FIG. 5. The displaycontent of FIG. 5 corresponds to the exemplary device connection of FIG.3.

[0083] From a viewpoint of the user, the interest lies in recognizingcontrol target nodes (the VTR 32 in the living room and the TV 33 in thechildren's room in this example) on the screen, and not in seeing whatis the topology of the IEEE 1394 network or the like, in the case ofusual device controlling. For this reason, the display on the screen ofthe PC 35 in this example is kept to the least necessary information asthe graphical user interface (GUI) such as “which device” in “whichroom”. For example, the information outlets themselves are notdisplayed. This is because it can be expected that the informationoutlets will not be the control targets of the user normally.

[0084] When the information as shown in FIG. 5 is presented by thescreen of the PC 35, for example, the user can carry out the remotecontrol of a desired device by selecting an icon of a desired device andcarrying out selection/input operation on an input screen that is openedin correspondence to the selected icon, using input devices such asmouse or pen or remote controller and input operations such as clicking,drag-and-drop, etc. For example, on the display screen of the PC 35 asshown in FIG. 5, the VTR 32 in the living room can be remote controlledfrom the PC 35 in the children's room by carrying out a prescribedoperation such as dragging a “VTR” icon in the living room and droppingit at a “TV” icon in the children's room, so that it becomes possible tocarry out the remote control to make a video recording reservation onthe VTR 32 in the living room from the PC 35 in the children's room, orplayback a video on the VTR 32 in the living room and display it on theTV 33 in the children's room.

[0085] Note that the remote control utilizing a screen as shown in FIG.5 and the control and data transfer between devices through 1394 networkcan be realized by the known techniques so that the detailed descriptionwill be omitted here.

[0086] It is also possible to present what service is provided at whichroom by describing a service provided by each node in the configurationmemory of each node.

[0087] As described, according to this first embodiment, it becomespossible to realize the management of physical locations of nodes orservice providing based on this management, which has been impossibleconventionally, by providing a region for describing a locationinformation in the configuration memory of each node.

[0088] <Second Embodiment>

[0089] The basic configuration used in this second embodiment is thesame as in the first embodiment, and the same concrete example as usedin the first embodiment will also be used for explanation, so that thedifferences from the first embodiment and the characteristic features ofthis second embodiment will be mainly described in the following.

[0090] In this second embodiment, the information outlet provided ateach room is assumed to be an IP node, i.e., a node capable of carryingout communications using the Internet protocol. Namely, the informationoutlet is going to have computer resources (such as CPU, dedicated IPprocessing chip, etc.) necessary for the operation as an IP node.

[0091] Then, it is also assumed that there is an Internet applicationfor presenting which devices are connected at each room, and providing aGUI environment in which commands for controlling each device can bereceived and commanded controls can be executed.

[0092] In this way, it is possible to realize the home networkmanagement or the management application creation which is not dependenton the link layer technologies such as IEEE 1394 or home automation,which is applicable regardless of a network type, and which isencompassing a plurality of networks (types).

[0093] This second embodiment also assumes a situation where theinformation outlets are provided in the home as shown in FIG. 1. Namely,the IEEE 1394 information outlets 11 to 15 are provided at a livingroom, a children's room, an entrance, a reception room, and a kitchen ofthe home respectively, and these information outlets 11 to 15 areinter-connected as shown in FIG. 2. Here, however, unlike the firstembodiment, it is not assumed that the information regarding a physicallocation is described in advance in the configuration memory of eachinformation outlet. The devices connected to these information outlets11 to 15 are the same as those shown in FIG. 3.

[0094] Now, the case of remote controlling the VTR 32 in the living roomfrom the PC 35 in the children's room will be considered again. In thiscase, the network management program operated at the PC 35 in thechildren's room activates a protocol aimed for inquiring a location, andcarries out the operation to inquire each node connected to the networkabout a location of that node. An exemplary procedure for this operationis shown in FIG. 6.

[0095] First, at a time of activation of the IEEE 1394 network, the PC35 can recognize its topology, that is, what devices are connected atwhich parts of the connected IEEE 1394 bus, through the self ID packetexchange and the configuration memory reading. However, here it is onlypossible to recognize up to the topology, and it is not possible torecognize a physical location information as to what devices are locatedin which room.

[0096] Consequently, the PC 35 transmits a location query packet ontothe IEEE 1394 as shown in FIG. 6. This packet is an IP packet to betransmitted to an IP multicast address that is allocated to the locationquery protocol in advance. Here, this IP multicast address is assumed tobe M1.

[0097]FIG. 7 shows an exemplary packet format for this location querypacket. As shown in FIG. 7, this location query packet is transmitted toa location query IP multicast address, and outputted to a port number(TCP or UDP port number) allocated in advance to the location queryprotocol. The payload contains an information indicating that this is apacket for query and the like.

[0098] Now, the information outlets 11 to 15 are set up in advance toreceive this location query packet, that is, to receive an IP packetdestined to the location query IP multicast address. In addition, it isassumed that each information outlet also has the information regardingits own physical location and the like internally as the configurationinformation by some method in advance. This information may have beendescribed in a ROM from the beginning or may be described in a RAM lateron, and the method of description here is assumed to be the same as thatfor describing the location information and the like into the IEEE 1394configuration memory in the first embodiment.

[0099] Now, taking the information outlet 12 as an example, theinformation outlet 12 that received the above described location querypacket recognizes that this is the location query packet from the portnumber and the payload, and transmits a reply packet (location replypacket) from each node describing the information regarding a physicallocation and the like, to the PC 35 which is a source of the query,after an elapse of a random time period since the receiving. Here, thereply packet is transmitted after a random time period in order toprevent concentration of reply packet transmissions from a plurality ofinformation outlets to the PC 35 into the same time period.

[0100]FIG. 8 shows an exemplary packet format for the location replypacket. As shown in FIG. 8, this location reply packet is transmitted toan address which is a source of the location query packet (that is theIP₃₅ which is the IP address of the PC 35). A port number (TCP or UDPport number) allocated in advance to the location query protocol is alsoattached similarly as in the location query packet (although the portnumber is to be reversed in the case of transmission and in the case ofreception). The payload describes an information indicating that thispacket is a packet for reply and that device (the information outlet 12in this case) is located at the children's room, along with theattribute information (the information indicating whether thatinformation outlet is movable or immovable, the information indicating aleaf port number, etc.).

[0101] In this way, the network management program of the PC 35 canobtain the information regarding physical locations of the informationoutlets 11 to 15, and by combining this information with the topologyinformation recognized earlier through the self ID packet exchange andthe configuration memory reading, it becomes possible to recognize(conjecture) a location at which each node exists.

[0102]FIG. 9 shows an exemplary operation procedure for the networkmanagement program in a form of an IP application. Namely, first, aphysical location of each information outlet is comprehended using thelocation query protocol, that is, which information outlet is located atwhich room is recognized (step S11). Then, for each information outlet,an information outlet under which a node connected to its leaf isexisting or the fact that no node is connected to its leaf issequentially recognized. That is, for each node or service that exists(step S12), whether that node or service is a leaf of some informationoutlet in view of the link layer topology or not is judged (step S13),and if so, that node or service is displayed or described under thatinformation outlet (step S14) whereas if not, that node or service isnot displayed or described under that information output (step S15). Inother words, the network management program in a form of an IPapplication regards a node that is connected to a leaf of theinformation outlet as existing in a room that is indicated by thelocation information and the like of that information outlet, anddisplays to the user a relationship between the rooms and the physicallocations of the nodes, on a screen as shown in FIG. 5 through GUIsimilar to that of the first embodiment.

[0103] The subsequent operations by the user and the correspondingoperations of the devices are the same as in the first embodiment.

[0104] Note that, in this second embodiment, the case of using thelocation query protocol has been described, but it is also possible torealize the same mechanism as the above, by providing a tag (such as<loc>, </loc>, etc.) that indicates the location information and thelike using HTTP, and exchanging this tag, for example.

[0105] Also, as for the registration of the location information and thelike, it is possible to use a method in which the information is storedin advance in a MIB (Management Information Base) and the registrationis realized by reading this information, or a method for notifying thelocation information and the like at a time of notifying the serviceusing the service location protocol (see IETF RFC 2165 for detail).

[0106] It is also possible to use these methods for notifying oracquiring the location information and the like in combination with thedisplay method according to the mechanism described above.

[0107] Also, by implementing this procedure in a form which is unrelatedto the lower layer technology, it is also possible to realize a locationquery mechanism that is applicable regardless of the network type.

[0108] <Third Embodiment>

[0109] The basic configuration used in this third embodiment is the sameas in the first embodiment, and the same concrete example as used in thefirst embodiment will also be used for explanation, so that thedifferences from the first embodiment and the characteristic features ofthis third embodiment will be mainly described in the following.

[0110] This third embodiment also assumes a situation where theinformation outlets are provided in the home as shown in FIG. 1. Thedifference from the first and second embodiments is that, in contrast tothe first and second embodiments where each information outlet was asingle IEEE 1394 node by itself, all (or a partial set) of theinformation outlets that are provided throughout the home willconstitute a single IEEE 1394 node 101 as shown in FIG. 10 in this thirdembodiment. Namely, it is a situation where it can be regarded that allthese information outlets 11 to 15 have the same IEEE 1394 node ID, andonly the physical locations of these 1394 connectors are physicallyseparated more than usual. Here, actual locations of the entities suchas CSR (Command Status Register), bus manager, etc., of the IEEE 1394 inthe configuration of FIG. 10 are not particularly limited.

[0111] Similarly as in the first embodiment, various devices areconnected to the information outlets 11 to 15 of this home. Here, thedevices connected to these information outlets 11 to 15 are assumed tobe the same as those shown in FIG. 3. Namely, a TV 31 and a VTR 32 areconnected to the information outlet 11 of the living room, a TV 33, aDVD 34 and a PC 35 are connected to the information outlet 12 of thechildren's room, a monitoring camera 36 is connected to the informationoutlet 13 of the entrance, and a TV 37 and a karaoke device 38 areconnected to the information outlet 14 of the reception room, while nodevice is connected to the information outlet 15 of the kitchen.

[0112] However, their topology from a viewpoint of the network isdifferent from the first and second embodiments, and the informationoutlets 11 to 15 as a whole are regarded as a single IEEE 1394 node 101as shown in FIG. 11. Consequently, in this case, it appears as if thereare nine IEEE 1394 nodes in this home. Here, such a node like 101 thatcontains a plurality of information outlets will be referred to as“information outlet group node”.

[0113] Now, similarly as in the first and second embodiments, thenetwork management mechanism of this third embodiment regards a 1394device connected to the information outlet of the living room exists inthe living room. Namely, a device connected to the information outlet ofthe living room will be presented to the user in such a form that itexists in the living room. To this end, it is also necessary here tomake it possible for a node connected to the network to recognize therelationship between the information outlets and their physicallocations.

[0114] For this reason, in this third embodiment, an informationregarding each information outlet is provided in the configurationmemory of the information outlet group node 101. A memory position,i.e., a register address for storing this information is uniquely set upin advance in the 1394 address space (the identical address is set upfor all the information outlet group nodes).

[0115]FIG. 12 shows an example of information to be stored in theconfiguration memory in this third embodiment. In this example, adedicated unit dependent directory for storing the information regardingeach information outlet (also referred hereafter as “port” in thisembodiment) is provided at a predetermined position (offset) of theconfiguration memory of the information outlet group node 101, and asits unit dependent directory, a dedicated unit dependent directory forstoring the location information of that unit (the port, i.e., theinformation outlet) is also provided and the location information ofthat port is stored therein.

[0116] More specifically, as shown in FIG. 12 for example, the portspecific (information outlet specific) information is stored as asub-directory, and the location information (the information regarding aphysical location, the information regarding movable/immovable), theinformation indicating a port that is a leaf, etc., similar to those ofthe first embodiment are stored as its further subdirectory, at thepredetermined positions in the configuration memory. The purpose andmethod for using these information are the same as in the first andsecond embodiments.

[0117] Similarly as in the first embodiment, in general, it appearscustomary to carry out the registration of such information at a time ofconstruction of the network, but a timing for the registration of suchinformation is not particularly limited in this third embodiment.

[0118] In the IEEE 1394, it is possible to recognize the IEEE 1394network topology through the exchange of self ID packets which is theinitialization phase of bus/network. This recognition of the topologyincludes the recognition as to which IEEE 1394 nodes are connected towhich ports of the information outlet group node.

[0119] When the PC 35 is assumed to be collecting the locationinformation and the like, in conjunction with the self ID packetexchange phase, the PC 35 can recognize that the information outlet 11,TV31 and VTR 32 exist in the living room, the information outlet 12, TV33, VTR34 and PC 35 exist in the children's room, the information outlet13 and monitoring camera 36 exist in the entrance, the informationoutlet 14, TV 37 and karaoke device 38 exist in the reception room, andthe information outlet 15 exists in the kitchen, by reading theinformation regarding a physical location on the configuration memory asshown in FIG. 12. Note that, as already mentioned above, things likethat this node is TV or this node is DVD, for example, are recognizedfrom the information described in the configuration memory of each node.

[0120] The display of the above recognition result on a screen at the PC35 can be realized by the display method shown in FIG. 5 as in the firstand second embodiments, for example. The subsequent controls of devicescan also be realized similarly as in the first and second embodiments.

[0121] <Fourth Embodiment>

[0122] The basic configuration used in this fourth embodiment is thesame as in the third embodiment, and the same concrete example as usedin the third embodiment will also be used for explanation, so that thedifferences from the third embodiment and the characteristic features ofthis fourth embodiment will be mainly described in the following.

[0123] This fourth embodiment also assumes a situation where theinformation outlets are provided in the home as shown in FIG. 1.Similarly as in the third embodiment, all (or a partial set) of theinformation outlets that are provided throughout the home willconstitute a single IEEE 1394 node, the information outlet group node101, as shown in FIG. 13 in this fourth embodiment.

[0124] The difference from the third embodiment is that each of theseports, that is, each of the information outlets 11 to 15, has its own IPaddress. Namely, it is a situation where the information outlet groupnode 101 is a single IEEE 1394 node from a viewpoint of IEEE 1394, butits ports (information outlets) are allocated with different IPaddresses as IP nodes from a viewpoint of IP. Here, the IP addresses tobe given can be either those of IPv4 or those of IPv6. For a host IDportion in the IP address, a combination of the port number value andthe EUI 64 (Extended Unique ID) value of the IEEE 1394 or its part canbe used for example.

[0125] As shown in FIG. 13, the IP addresses of the nodes are assumed tobe IP₁₁ to IP₁₅ for the information outlets 11 to 15, and IP₃₁ to IP₃₈for the TV 31 to the karaoke device 38, respectively.

[0126] In this fourth embodiment, similarly as in the second embodiment,it is assumed that there is an Internet application for presenting whichdevices are connected at each room, and providing a GUI environment inwhich commands for controlling each device can be received and commandedcontrols can be executed, under a situation where the information outletprovided at each room is assumed to be an IP node, i.e., a node capableof carrying out communications using the Internet protocol. Because ofthe use of IP, it is possible to realize the home network management orthe management application creation which is not dependent on the linklayer technologies such as IEEE 1394 or home automation and which isapplicable regardless of a network type.

[0127] Also, in this fourth embodiment, similarly as in the secondembodiment, it is not assumed that the information regarding a physicallocation is described in advance in the configuration memory of eachinformation outlet.

[0128] Now, the case of remote controlling the VTR 32 in the living roomfrom the PC 35 in the children's room will be considered here onceagain. In this case, the network management program operated at the PC35 in the children's room activates a protocol aimed for inquiring alocation, and carries out the operation to inquire each node connectedto the network about a location of that node. This protocol is basicallythe same as in the second embodiment.

[0129] Namely, by the procedure shown in FIG. 6, first, the PC 35 canrecognize the topology of the IEEE 1394 network, that is, what devicesare connected at which parts of the connected IEEE 1394 bus, through theself ID packet exchange and the configuration memory reading. Here,however, similarly as in the second embodiment, it is only possible torecognize up to the topology, and it is not possible to recognize aphysical location information as to what devices are located in whichroom.

[0130] Consequently, the PC 35 transmits a location query packet ontothe IEEE 1394 as shown in FIG. 6, similarly as in the second embodiment.This packet is an IP packet to be transmitted to an IP multicast addressthat is allocated to the location query protocol in advance. Here, thisIP multicast address is assumed to be M1.

[0131] Similarly as in the second embodiment, this location query packethas a packet format as shown in FIG. 7. At each of the informationoutlets 11 to 15, the location query protocol is activated in advanceand the set up to always receive a packet destined to this locationquery IP multicast address M1 is made in advance.

[0132] In addition, it is assumed that each information outlet also hasthe information regarding its own physical location and the likeinternally as the configuration information by some method in advance.This information may have been described in an internal ROM from thebeginning or may be described in a RAM later on, and the method ofdescription here is assumed to be the same as that for describing thelocation information into the IEEE 1394 configuration memory in thefirst embodiment.

[0133] Now, taking the information outlet 12 as an example, theinformation outlet 12 that received the above described location querypacket recognizes that this is the location query packet from the portnumber and the payload, and transmits a reply packet (location replypacket) describing the information regarding a physical location and thelike, to the PC 35 which is a source of the query, after an elapse of arandom time period since the receiving time. For this informationregarding a physical location, the information written in the internalROM or RAM mentioned above can be used, for example. To this end, aprogram for transmitting this location reply packet is set such that itrecognizes the information regarding its own physical location and thelike in advance, prior to transmission of the location reply packet.

[0134] The location reply packet has a packet format as shown in FIG. 8.The payload describes an information indicating that this packet is apacket for reply and that device (the information outlet 12 in thiscase) is located at the children's room, along with the attributeinformation (the information indicating whether that information outletis movable or immovable, the information indicating a leaf port number,etc.).

[0135] In this way, the network management program of the PC 35 canobtain the information regarding physical locations of the informationoutlets 11 to 15, and by combining this information with the topologyinformation recognized earlier through the self ID packet exchange andthe configuration memory reading, it becomes possible to recognize(conjecture) a location at which each node exists.

[0136] More specifically, similarly as in the second embodiment,according to the procedure shown in FIG. 9, a physical location of eachinformation outlet is comprehended using the location query protocol,that is, which information outlet is located at which room isrecognized, and then, for each information outlet, an information outletunder which a node connected to its leaf is existing or the fact that nonode is connected to its leaf is sequentially recognized. In otherwords, the network management program in a form of an IP applicationregards a node that is connected to a leaf of the information outlet asexisting in a room that is indicated by the location information and thelike of that information outlet, and displays to the user a relationshipbetween the rooms and the physical locations of the nodes, on a screenas shown in FIG. 5 through GUI similar to that of the first embodiment.

[0137] The subsequent operations by the user and the correspondingoperations of the devices are the same as in the first embodiment.

[0138] Now, the information outlet group node 101 has only one linklayer address but there are plural IP addresses corresponding to theports, so that there is a need to provide some programs for dealing withthis situation.

[0139] First, when one information outlet belonging to the informationoutlet group node 101 receives the IEEE 1394 packet, there are caseswhere the destination 1394 node ID is the node ID of the informationoutlet group node 101 and the destination IP address of the encapsulatedinternal IP packet is the IP address of another port different fromitself.

[0140] In this case, the IP processing function of each port carries outthe broadcast with respect to the internal wiring sides (internal sidesof FIG. 10) of the information outlet group node 101. Namely, that IPpacket is forwarded such that it reaches to all the information outletsin that information outlet group node 101.

[0141] In this way, even in the case where values of the link layer IDthat can be given to the nodes are to be limited, it is possible toeffectively disregard such a limitation as far as IP addresses areconcerned (for example, IPv6 has an address space of 128 bits), so thatit becomes possible to provide an IP processing unit at each port andthereby realize an intelligent port, i.e., an intelligent informationoutlet having various functions such as network layer implementation ofthe location query protocol, implementation of power consumption queryprotocol, filtering of passing data, etc.

[0142] In addition, it becomes possible to deliver an IP packet that isallocated to some specific port to a communication port which properlyhas that IP address. This is because it cannot specify the destinationport of the IP packet according to the link layer ID alone in this case,but it becomes possible to deliver the IP packet properly to that IPprocessing unit by using the above described broadcast function. Also,by using the broadcast information, it also becomes possible to reduceworks, hardware amount and memory amount that are required in preparingthe routing table of IP addresses internally and carrying out therouting.

[0143] Note that each port (information outlet) that received a packetis made not to forward that packet even if its destination IP address isnot that node itself, if that packet was received from the internalside. This provision is necessary in order to prevent an indefinite loopin the above described procedure.

[0144] Next, a method for handling the case of receiving the inverse ARP(Address Resolution Protocol) will be described. Here, the IP processingunit of each information outlet that received the inverse ARP handles itby replying the own IP address. For example, when the inverse ARParrives with respect to the information outlet 11, the IP processingunit of the information outlet 11 will return its own IP address, thatis IP₁₁, as a reply.

[0145] As described, according to the present invention, it becomespossible to realize the management of physical locations ofcommunication devices and the service providing based on thismanagement, which have been impossible conventionally, by providing aregion for describing an information regarding a physical location inthe configuration memory of each communication device.

[0146] Note that the embodiments described above are directed to thecase where management targets or operation targets are devices, and theprocessing regarding each device and its physical location, the GUI orremote control service providing based on that, etc., have beendescribed, but it is also possible to deal with the case wheremanagement targets or operation targets are services and the processingregarding each service and its physical location or a location where itis provided (a physical location of a node for providing that service)is carried out similarly. For example, when a PC is connected to theinformation outlet in the reception room, and this PC provides a certainservice A (e.g. Web server), it is possible to realize a configurationwhere this service A is displayed at the reception room portion on thedisplay screen similar to that of FIG. 5 on the PC 35 in the children'sroom, and this service A can be received at the PC 35 in the children'sroom by selecting the service A on the screen using a mouse.

[0147] Also, the above description presupposes the use of IEEE 1394 forthe home network, but the present invention is equally applicable to theother network techniques such as Ethernet, USB (Universal Serial Bus),and controlled LAN such as power line LAN.

[0148] Also, each function described above can be realized as software,and it is also possible to realize a computer readable medium thatrecords a program for causing a computer to execute each procedure ofmeans described above.

[0149] It is also to be noted that, besides those already mentionedabove, many modifications and variations of the above embodiments may bemade without departing from the novel and advantageous features of thepresent invention. Accordingly, all such modifications and variationsare intended to be included within the scope of the appended claims.

What is claimed is:
 1. A communication device, comprising: at least onecommunication unit for carrying out communications through a connectednetwork, having communication ports for connecting nodes through whichdata are to be exchanged by the nodes; and a configuration informationmemory unit for storing a configuration information regarding aconfiguration of the communication device, having a region fordynamically describing a location information regarding a physicallocation of either the communication device or said at least onecommunication unit.
 2. The communication device of claim 1, wherein thecommunication device has a plurality of communication units, eachcommunication unit having communication ports for connecting nodesthrough which data are to be exchanged by the nodes, and said region ofthe configuration information memory unit dynamically describes alocation information regarding a physical location of each communicationunit.
 3. The communication device of claim 1, wherein said region of theconfiguration information memory unit also describes an informationregarding whether the communication device is movable or immovable. 4.The communication device of claim 1, wherein said region of theconfiguration information memory unit also describes an informationindicating a communication port which is a leaf of a network structureamong the communication ports.
 5. A communication device, comprising: aconfiguration information collection unit for collecting a configurationinformation of a connected network; a location information collectionunit for collecting at least a location information regarding a physicallocation of a prescribed node connected to the network; and a managementunit for managing physical locations of other nodes/services that areconnected to the prescribed node, by regarding the other nodes/servicesas existing at an identical physical location as the physical locationof the prescribed node as specified by the location information.
 6. Thedevice of claim 5, further comprising: a display unit for displaying toa user the physical locations of the other nodes/services as identicalto the physical location of the prescribed node as specified by thelocation information.
 7. The device of claim 5, wherein the locationinformation collection unit also collects an information regarding aregion corresponding to a leaf of the prescribed node, and themanagement unit manages physical location of selected othernodes/services that are connected to the region corresponding to theleaf of the prescribed node alone, by regarding the selected othernodes/services as existing at the identical physical location as thephysical location of the prescribed node as specified by the locationinformation.
 8. A communication device, comprising: at least onecommunication unit for carrying out communications through a connectednetwork, having communication ports for connecting nodes through whichdata are to be exchanged by the nodes; a memory for storing a locationinformation regarding a physical location of the communication device;and a reply unit for returning a reply packet containing the locationinformation as stored in the memory, to a node that is a source of aquery packet through the communication unit, upon receiving the querypacket for inquiring a physical location of the communication devicethrough the communication unit.
 9. A communication device, comprising:at least one communication unit to which a single link layer ID isgiven, for carrying out communications through a connected network,having a plurality of communication ports for connecting nodes throughwhich data are to be exchanged by the nodes; and a network layerprocessing unit for carrying out a network layer processing related tothe communications, by assigning different network layer addresses tothe communication ports.
 10. The device of claim 9, wherein when apacket destined to the link layer ID given to the communication unit isreceived from one communication port through the connected network, thenetwork layer processing unit broadcasts at least a part of the packetwith respect to other communication ports different from said onecommunication port if the packet is destined to a network layer addressdifferent from one network layer address assigned to said onecommunication port.
 11. A network information management method in acommunication device having at least one communication unit for carryingout communications through a connected network, the method comprisingthe steps of: collecting a configuration information of the connectednetwork; collecting at least a location information regarding a physicallocation of a prescribed node connected to the network; and managingphysical locations of other nodes/services that are connected to theprescribed node, by regarding the other nodes/services as existing at anidentical physical location as the physical location of the prescribednode as specified by the location information.
 12. A locationinformation notification method in a communication device having atleast one communication unit for carrying out communications through aconnected network and a memory for storing a location informationregarding a physical location of the communication device, the methodcomprising the steps of: receiving a query packet for inquiring aphysical location of the communication device through the communicationunit; and returning a reply packet containing the location informationas stored in the memory, to a node that is a source of the query packetthrough the communication unit.